1. Field of the Invention
This invention relates to electric discharge lamps and has particular reference to an improved fluorescent lamp of compact size and high brightness that is suitable for use in various kinds of residential and commercial lighting fixtures.
2. Description of the Prior Art
Electric discharge lamps having envelopes which are internally partitioned to provide one or more elongated discharge paths are well known in the art. U.S. Pat. Nos. 1,963,962 and 2,121,333 granted to Barclay disclose such lamps. U.S. Pat. No. 2,561,868 issued July 24, 1951 to Jenkins et al also discloses a multi-discharge lamp having an outer envelope which contains several open-ended arc tubes. The tubes are held in place by a baffle assembly that is attached to a stem, which is sealed to and closes the outer envelope, and by wire springs of ring-like configuration that surround the tubes and engage the wall of the outer envelope. The discharges are U-shaped and pass through adjacent pairs of tubes or follow straight paths through the tubes to a common electrode which is located at the domed end of the outer envelope.
High-pressure discharge lamps which contain a plurality of electrodes that are disposed within a common envelope and support simultaneous arc discharges are disclosed in U.S. Pat. Nos. 2,459,516 and 3,304,457.
A single-ended fluorescent lamp having a tubular envelope that contains a concentric glass cylinder and several electrodes which are sequentially energized in such a manner that the arc passes through the cylinder and sweeps around the annular chamber defined by the cylindrical partition and the envelope is disclosed in U.S. Pat. No. 3,609,436 issued Sept. 28, 1971 to Campbell.